South Africa's Oscar Pistorius made history on Saturday when he became the first double amputee to compete in an athletics event at the Olympics.

The 25-year-old qualified for the semifinals of the 400 metres by running a season's best of 45.44 seconds in finishing second.

Pistorius, who had both legs amputated below the knee before he was aged one, because of a congenital condition, runs on carbon fibre blades.

He is also due to run in the 4x400m relay at the Games.

Pistorius said the occasion had almost overwhelmed him, as he at last realised his dream after battling to convince the authorities to let him make it happen for several years.

"I was so nervous this morning," he said.

"I didn't know whether to cry. I had a mixture of emotions. It was the most amazing experience, the crowd was amazing. I saw the South African flag."

Pistorius added he owed a lot to his coaches for their support.

"I've got to thank my team, they trust me, I trust them. We've been together for nine years."

Pistorius, known as the 'Blade Runner', competed in the Athens 2004 and Beijing 2008 Paralympics.

"It was the most amazing experience,
the crowd was amazing. I saw the South African flag."

But he was given the green light to make his debut in the Olympics following studies that found his prosthetics give him no advantage over his able-bodied rivals.

His personal best is 45.07sec in the 400m and Pistorius came to London wanting to break the 45-second barrier.

"When I found out I had made the team, a certain pressure left and another pressure came in," he said prior to the Games.

"It hits you when you're standing on the starting blocks. At Athens and Beijing, that's when it really dawned upon me." He is clear to compete on condition he uses the same prosthetic legs that have been used in Paralympic sport since 1996.

Pistorius said exhaustive tests had proved that running on blades gave him no advantage.

Pistorius -- 13 kilogrammes lighter than he was in Beijing -- said he had no worries about competing in both the Olympics and the Paralympics, where his 89-year-old grandmother will be coming to watch him.

Meanwhile, hopes of Khotso Mokoena adding to South Africa's medals tally were dashed on Saturday night when he disappointed in the long jump final.

The 27-year-old finished eighth with a best jump of 7.93 metres.

It was a far cry from his season best of 8.29m and his personal best of 8.50m which saw him win a silver medal at the 2008 Beijing Games.

Mokoena's first leap was his best distance as he followed it up with a no-jump, 7.62m and three consecutive no-jumps.

The gold medal went to Greg Rutherford of Great Britain with his distance of 8.31m.

South African track cyclist Bernard Esterhuizen finished 11th overall in the men's sprint event.

Earlier, defeated by German rider Robert Forstemann in the first heat, he was given a second chance in the repechage.

Esterhuizen beat Spanish cyclist Hodei Uria Mazquiaran and Miao Zhang from China to go through to the last eight.

Up against Great Britain's Jason Kenny, he was outclassed but went through to his second repechage, where he again came up against Forstemann, with the same result, ending his Olympic competition.

Jean Greeff lifted a personal best 313kg in the weighlifting men's 94kg category although it was a long way off from the medal winners for the 22-year-old.

In sailing, the men's 470 competitors Jim Asenathi and Roger Hudson completed races five and six, and are still languishing at the bottom of the standings.

They still have four more races to go before any boats are eliminated.

The South African women's hockey team will have to be content with a bottom-half finish to their Olympic campaign after losing 1-0 to Australia in their penultimate pool B contest in London on Saturday.

The loss ensured South Africa would not be able to compete for a semifinal place as they remained without a win after four games and in danger of losing all their pool games at the London Games.

The South Africans conclude their campaign against the US on Monday.

Gillian Sanders completed the women's triathlon final in a time of two hours, two minutes and 28 seconds (2:02:28), leaving her in 19th position, nearly three minutes behind Swiss winner Nicola Spirig (1:59:48).

Fellow South African athlete Kate Roberts finished behind Sanders in 22nd place in a time of 2:02:46.

Additional reporting from Sapa-AFP